Find a good patch of Showy Milkweed (Asclepias speciosa) and you are likely to spot these boldly colored longhorn beetles. As the name suggests, they specialize on milkweed; the larvae feed on the roots and the adults feed on the leaves and flowers. By feeding on milkweed, these insects absorb the plant’s chemicals and are toxic to potential predators. Adults will be present through September, with the larvae boring into the stems and overwintering in the roots.
Photo by Glenn Marangelo on 9/20/20 in Missoula, MT